Characterization of the severe acute respiratory syndrome coronavirus nucleocapsid (SARS-CoV N) protein

劇烈上呼吸道感染冠狀病毒鞘蛋白特性之探討

彭翠儀(Tsui-Yi Peng)

指導教授 ： 李寬容 ； 譚婉玉

國立清華大學/生命科學院/生命科學系/博士(2008年)

https://doi.org/10.6843/NTHU.2008.00106

摘要

Abstract
In early 2003, a novel coronavirus named severe acute respiratory syndrome coronavirus (SARS-CoV) caused a worldwide outbreak disease, SARS, displayed a high infectious ability. SARS Coronavirus nucleocapsid (N) protein is one of most abundant viral protein in infected cells, it is a phosphoproteins and plays multiple functions in viral synthesis and regulates host cells signal transduction. The N protein contains an arginine/serine (RS)-rich motif in its middle region, the role of this motif still need to be identified. In this study, we demonstrate that the SARS-CoV N protein is phosphorylated through RS-rich motif in vitro and in vivo. N protein could bind specific (viral) and non-specific (random) RNA, our results indicated that SRPK1 phosphorylation of the SR motif can reduces the multimerization ability of N protein. Moreover, SARS-CoV N protein impaires the translation via the RS motif, nevertheless, phosphorylation of the N protein can partly rescue the translation. Additionally, SARS-CoV N proteins localize to both the cytoplasm and the nucleolus, we observed that N protein translocates to cytoplasmic stress granules (SGs) when cells under stress, however, SRPK1 overexpression can inhibit N protein translocate to SGs. Taken together, SR motif regulates multiple functions of SARS-CoV N protein. Further, hypo- or hyper- phosphorlation of the N protein impaired its activity of these regulations, including multimerization and translation control.
Another RNA-binding protein, hnRNP Q, is one of the SMN RNA-associating proteins. We observed that the RGG box of hnRNP Q interacts with SMN RNA, and C-terminal domain of hnRNP Q1 mediates RNA binding and self association.

關鍵字

SARS ； coronavirus ； nucleocapsid ； RS-motif ； phosphorylation ； translation

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